Responsiveness is always enabled and there is no link to disable it

[![enter image description here][1]][1]:

What I'd *really* like is to be able to disable the responsive "change depending on your real estate" and always just have the left bar and main area, without the bar on the right. 

Perhaps a way to say "I always want to see x and y... but if you can fit z in then go ahead knock yourself out."

We could call it "amenable" mode.

  [1]: https://i.sstatic.net/UCVXX.jpg